This invention relates generally to accessories for toy or model railroad layouts and more particularly to an improved combination block signal and train detector for such layouts.
There is a demand for model railroad accessories that simulate signals used on full sized railroads. One such accessory is a block signal. A block signal controls the passage of trains by providing a red or green signal right to the engineer indicating whether it is safe to pass the block signal.
In full size trains, block signals are controlled by a variety of complex mechanisms the precise duplication of which is not practical in model train layouts. Accordingly, it has become common to provide block signals in model train layouts that turn red when a train approaches and turn green after the train has passed. Previously, known block signals have been relatively simple devices including a red light and a green light that can be selectively illuminated by applying appropriate activating signals to inputs of the block signal. The inputs to the block signals have come from a variety of sources generally referred to as train detectors. Known train detectors include detectors that use a section of isolated track that is responsive to a train passing over it and light or magnetic sensors to detect the presence of a passing train.
Heretofore, proving block signals responsive to the passage of trains has required the use of multiple devices and sometimes complex wiring connections between them. It is an object of this invention to provide a combination of a block signal and train detector that greatly simplifies installation compared with known approaches.
It is another object if this invention to provide a combination block signal and train detector that can be easily synchronized with similar devices positioned at remote locations on a model train.
It is another object of the invention to provide a combination block signal and train detector that uses simple inexpensive circuitry that allows the device to be manufactured and sold at reasonable prices
Briefly stated, and in accordance with a presently preferred embodiment of the invention, a combination model train sensor and block signal includes a train proximity sensor, a red signal light, a green signal light, and a controller connected to the proximity sensor and the red and green signal lights. The controller turns on the green signal light and turns off the red signal light when the proximity sensor indicates the absence of a train, and turns on the red signal light and turning off the green signal light when the train proximity sensor indicates the presence of a train.
In accordance with another aspect of the invention, the train proximity sensor of the model train sensor and block signal includes a light source, preferably an infrared light source, and a light detector, preferably an infrared light detector, arranged to reflect and detect from a passing train to indicate its presence.
In accordance with another aspect of the invention, the combination model train sensor and block signal includes an output connected to the train proximity sensor for producing an output signal when the sensor indicates the presence of a train, which output can be used for controlling a remote block signal.
In accordance with another aspect of the invention, the combination model train sensor and block signal includes an input, responsive to a signal received from a remote sensor, for controlling the illumination of the red and green lights and synchronizing two block signals.
In accordance with another aspect of the invention, the combination model train sensor and block signal includes a combination input/output connected to the controller, the input/output producing a train present signal when the train proximity sensor indicates the presence of a train and being responsive to an externally applied train present signal for turning the red light on and the green light off even when the local train proximity sensor indicates the absence of a train.
In accordance with another aspect of the invention, the combination model train sensor and block signal includes a first transistor switch for turning on the green light, the first transistor switch preferably connected to be normally on and a second transistor switch having an input connected to the train proximity sensor and an output connected to the red signal light and to an input of the first transistor switch to turn the red signal light on and apply an off signal to the input of the first transistor switch to turn the green signal off. The second transistor switch is preferably connected to be normally off.
In accordance with another aspect of the invention, the input/output is connected to the second transistor switch.